Another World I has an infinite corridor as its focal point; the effect of which is the reason Escher disliked it. It also has what appears to be an oil lamp hanging over the bird-man.

Another World II has, in essence, a very open room instead of a corridor. It has a horn hanging in the window adjacent to the one in which the bird-man stands.

As for the purpose or deeper meaning of these works, Escher left them open to interpretation, as he did with nearly all his works. The closest he ever came to giving a purpose to a work was to urge people to think along multiple paths, as everything looks different from another vantage point.

This writeup is based on the works mentioned found on pages 134-135 in The Magic of M. C. Escher, ISBN 0-8109-6720-0